Compressor

ABSTRACT

A compressor for use in a compression type refrigeration cycle, in which the direction of a refrigerant flow passage is sharply changed at the refrigerant suction port, whereby lubricating oil mixed in the refrigerant in the refrigeration cycle is effectively separated and thereafter collected rapidly by making use of the dynamic pressure of said refrigerant and a pump.

United States Patent 9 Oshima et a1.

111 3,796,522 1451 Mar. 12', 1974 COMPRESSOR [75] Inventors: Ryoichiro Oshima; Seigo Miyarnoto;

Kenichi Kawashima, all of Hitachi, Japan [73] Assignee: Hitachi, Ltd., Tokyo, Japan [22] Filed: June 28, 1971 [2]] Appl. No.: 157,390

[30] Foreign Application Priority Data June 29, 1970 Japan 45/56040 [52] U.S. C1 418/15, 418/88, 418/171,

[51] Int. CL... F0 lc 21/04, Bold 45/00, F04c 29/02 [58] Field 6156611611... 418/15, 88, 171, 97-99, 418/76; 55/461, 466; 62/470, 471

[56] References Cited UNITED STATES PATENTS 3,135,460 6/1964 Galin 418/88 3,398,886 8/1968 Roach.... 3,184,157 5/1965 Galin 3,618,577 11/1971 Shaw et al 3,045,778 7/1962 Mosbacher 1,486,835 3/1924 Hill 1,953,253 4/1934 Ogilvie 3,641,744 2/1972 Culbert et a] 3,432,089 3/1969 Schibbye 418/88 Primary ExaminerCarlton R. Croyle Assistant Examiner.lohn .1. Vrablik Attorney, Agent, or Firm-Craig and Antonelli [57] ABSTRACT A compressor for use in a compression type refrigeration cycle, in which the direction of a refrigerant flow passage is sharply changed at the refrigerant suction port, whereby lubricating oil mixedin the refrigerant in the refrigeration cycle is effectively separated and thereafter collected rapidly by making use of the dynamic pressure of said refrigerant and a pump.

4 Claims, 11 Drawing Figures PATENTEDNAR 12 m4 3; 796; 522

sum 2 m 3 Ill.

INVENTORS RYOICHIRO 0 H IMA SEIGO MIYAMOTO M1 KENICHI KAWASHIMA aa wtwflt 4, m

ATTORNEYS PATENTED MR 12 I974 SHEET 3 0F 3 4 INVENTOR5 5 6 RYOKHIRO HlMA S5160 MIYAMOTOM KENICHI KAWASHIMA ATTORNEYS COMPRESSOR I BACKGROUND OF THE INVENTION Rotary machines and equipments are generally provided, with an oil tank for lubricating sliding portions, such as bearings,'to prevent the burning of said portions by frictional heat.

In a compressor used in a compression type refrigeration cycle, the failure of the sliding portions is also an important factor to determine the service life and quality of the compressor. For this reason, the utmost effort has been made to prevent the burning of the sliding portions by equipping the compressor with an oil tank and constantly supplying lubricating oil to said portions by making use of centrifugal force, capillary phenomenon or a gear pump.

This type of compressor, unlike the ordinary rotary machines and equipments, is constructed such that the sliding portions communicate with a refrigerant passage. Moreover, hydrocarbon fluoride-type gases commonly used as a refrigerant have the property of being very easily soluble in lubricating oils. Therefore, it is usual that a certain amount of lubricating oil flows in the circuit along with the discharged refrigerant. However, a high degree of vacuum is produced abruptly at the start or acceleration of the compressor, a lubricating oil bubbling phenomenon occurs due to sudden boiling of the refrigerant dissolved in the lubricating oil in the oil tank, with the result that a large quantity of lubricating oil is introduced into the refrigerant circuit through the gap between the cylinder blocks and the shell of the compressor. Such a phenomenon has been liable to occur particularly in the case of compressors of air conditioning units for vehicles, and the introduction of a large quantity of lubricating oil into the refrigerant circuit has resulted in a shortage of lubricating oil in the compressor, causing such trouble as seisure of the sliding portions."

Such a phenomenon could be avoided by eliminating the gap between the cylinder blocks and the shell but in practice, the formation of some gap is inevitable in consideration of a temperature rise of the compressor during use. Alternatively, it may be considered to provide the compressor with a large oil tank so as not to invite a lubricating oil shortage even when some amount of the lubricating oil is admitted into the refrigerant circuit. However, such measure is undesirable because this type of compressor should be as small in size as possible in consideration of the mounting space, etc. and furthermore the introduction of a large amount of oil into the refrigerant circuit will result in a lowering of the cooling activity of the refrigerant and hence a lowering of the cooling capacity. 7

In view of the above problem, US. Pat. No. 3,352,485 proposes to form oil channels in the outer surface of the cylinder block and separate and collect the oil, present in the refrigerant sucked from the suc tion port of the compressor, through said oil channels. Further, U.S. Pat. No. 2,835,436 proposed to provide an impeller at the suction port of the compressor and centrifugally separate and collect the oil having a relatively large specific gravity by said impeller.

Besides the above-mentioned publications, Japanese Utility Model Publication No. 3416/67 proposes, as a method of preventing an oil shortage, to provide on the front stage of the oil tank a small oil chamber communicating with said oil tank by a small aperture and communicate said oil chamber with the gear pump, so that only a small amount of oil stored in said oil chamber may be sucked even when a high degree of vacuum is produced in the compressor and acts in the oil tank.

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a compressor comprising oil separating means provided at a refrigerant suction port thereof, by which the oil present in the refrigerant is separated and collected early.'

Another object of the invention is to provide a compressor of the character described above in which an oil suction port of a gear pump is shaped in a unique configuration so that the oil separated by the oil separating means may be quickly colllected by said gear pump.

A feature of the present invention resides in the arrangement in which a refrigerant passage at the refrigerant suction port of the compressor has a vertical passage portion and a horizontal passage portion and said vertical passage portion is extended beyond said horizontal passage portion to form an oil separating cham- BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation view of an ordinary swash plate compressor;

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1;

FIG. 3 is a diagrammatic view of a side cover being positioned adjacent a suction port of a swash plate compressor of an embodiment of the present invention; FIG. 4 shows a back surface of the side cover of FIG. 3;

FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 4;

FIG. 6 shows a relative position between a suction port and a discharge port of an ordinary gear pump which is used for supplying oil into the swash plate compressor;

FIG. 7 shows a relative position between a suction port and a discharge port of a gear pump utilized in the present invention; I

FIG. 8 through 10 are explanative views of functions of said gear pump; and

FIG. 1 l is a cross-sectional view of the compressor of the instant invention illustrating the suction port of the gear pump in communication with an oil pan.

DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described hereinafter with reference to the drawings. An ordinary swash plate compressor 1 has two cylinder blocks 2, 2' each having three cylinders 3 therein. In the cylinder is slidably disposed a piston 4 which is in engagement at its mid portion with a swash plate 7 through a ball 5 and a slipper 6. The swash plate 7 is fixedly mounted on a shaft 8 supported in the cylinder blocks 2, 2' through a radial bearing 9 and a thrust bearing 10. The cylinder blocks 2, 2' are inserted in a shell 11 and side covers 13, 14 are fitted to the side faces of said cylinder blocks with a valve plate 12 interposed therebetween respectively. In the side cover 13 are formed a low pressure chamber 15 and a high pressure chamber 16 which are respectively communicated with the cylinder 3 through a valve portion. The low pressure chamber 15 is also communicated with a suction passage 17. I

The suction passage has a vertical passage portion 18 and a horizontal passage portion 19 connected at right angles to each other. The vertical passage portion 18 is extended further from the intersection with the horizontal passage portion 19, .to form a separation chamber 20 which is communicated with the suction side of a gear pump 22 through a collecting passage 21 and a communication port (21'). An inner gear 23 of the gear pump 22 is fixedly mounted on the shaft 8 within a gear case 24. A suction port consists of a main suction port and an auxiliary suction port 26, and the main suction port 25 communicates with an oil pan 27, while the auxiliary suction port 26 communicates with the collecting passage 21. A discharge port 28 communi-,

cates with a passage (not shown) formed in the shaft 8 for supplying oil to the respective bearings 9, 10 and the ball 5 therethrough.

Now, the relative position of the suction port of the gear pump 22 be described. In general, the suction port and discharge port of the gear pump respectively have the shapes as shown in FIG. 6. The shapes of the suction port 25 and the discharge port 28 are determined such that, with a a representing the points of contact between the inner gear 23 and an outer gear formed on the inner side of gear case 24'when the enclosed volume-is largest, and b b the points of contact at a portion where said volume is smallest, as shown, for example, in FIG. 8, the length of the suction port 25 will be from b to a and the width thereof is slightly larger than the width between the root circles of the inner gear 23 and the outer gear, and the length of the discharge port 28 will be from 12 to a and the width thereof is similar to that of the suction port 25.

Here, if the suction port 25 starts from b and is shorter than a the enclosed volume is in the process of increasing but, since the suction port 25 is short, no fluid is sucked and accordingly the pressure drops. In the state of FIG. 9, the suction port 25 is only up to a and the amount of fluid sucked from the suction port is represented by the hatched volume. As the rotation advances in that state, the pressure drops and discharge starts from the moment when the state of FIG. 8 is produced. If the auxiliary suction port 26 is provided which will contact the point a, in the state of the inner gear and the outer gear shown in FIG. 9, so as to suck the fluid therethrough, an amount of fluid equal to the balance of the hatched volumes shown in FIGS. 8 and 9 will be sucked from said auxiliary suction port 26. The auxiliary suction port 26 must also be in contact with the suction port side of the hatched portion of FIG. 8, since the discharge commences at the moment when the state of FIG. 8 starts to change to the next state.

FIG. 10 shows the case in which the size of the auxiliary suction port 26 is varied. It will be seen that the amount of fluid sucked from the main suction port 25 is larger than in the case of FIG. 9. t Thus, it will be understood that the proportion of the amount of fluid sucked from the main suction port 25 to the amount sucked from the auxiliary-suction port 26 can be varied by suitably selecting the size of said auxiliary suction port 26. In other words, a constant amount of fluid is always sucked from the main and auxiliary suction ports. In the present invention, the main suction port 25 communicates with the oil pan 27 via communication port 29 (FIG. 11) and the auxiliary suction port 26 with the separation chamber 20, so that the oil in both the oil pan and the separation chamber is positively sucked. Should the main suction port 25 only be in communication with the oil pan 27 and the separation chamber 20, the refrigerant in the suction passage 17 would be sucked in a larger amount than the oil in the oil pan 27. Such a discrepancy will not occur in the pump of the instant invention.

It should be understood that the vertical passage portion and the horizontal passage portion of the suction passage 17 are not necessarily at right angles but at any angle which is large enough to separate the oil.

. It should also be noted that, though, in the described embodiment, the main suction port is open in the pump at a location where the pump is in the initial stage of its suction stroke and said auxiliary suction port at a location where the pump is in the latter stage thereof, the main and the auxiliary suction ports may be open in said pump at either location where the pump is in the initial and the latter stages of its suction stroke.

It should also be understood that the application of the subject compressor is not restricted only to car coolers but the compressor may be used in a wide range in the field of this type of compressor.

We claim:

1. A compressor used in compression type refrigeration cycles having suction passage means, oil separating separating chamber having a bottom portion directly communicated with said suction port of said oil pump means for returning the oil from said separating chamber to said oil pump means.

2. A compressor according to claim 1 wherein an oil collecting means of a smaller diameter than said oil separating chamber is provided at the bottom of said chamber in communication with said oil pump means.

3. A compressor according to claim 1 wherein said suction port of said oil pump means consists of a main suction port and an auxiliary suction port said oil separating chamber being in communication with said auxiliary suction port and said main suction port being in communication with an oil pan.

4. A compressor as defined in claim 3, wherein said main suction port is open in said pump at a location where the pump is in the initial stage of its suction stroke and said auxiliary suction port at a location where said pump is in the latter stage of its suction stroke. 

1. A compressor used in compression type refrigeration cycles having suction passage means, oil separating means and oil pump means for supplying lubricating oil to said compressor provided with a suction port, said oil separating means comprising a vertical passage portion in the suction passage means, a horizontal passage portion substantially perpendicular to and intersecting with said vertical passage portion, and an oil separating chamber in said vertical passage portion beyond the intersection with said horizontal passage portion, said oil separating chamber having substantially the same cross-section as said vertical passage portion, said oil separating chamber having a bottom portion directly communicated with said suction port of said oil pump means for returning the oil from said separating chamber to said oil pump means.
 2. A compressor according to claim 1 wherein an oil collecting means of a smaller diameter than said oil separating chamber is provided at the bottom of said chamber in communication with said oil pump means.
 3. A compressor according to claim 1 wherein said suction port of said oil pump means consists of a main suction port and an auxiliary suction port said oil separating chamber being in communication with said auxiliary suction port and said main suction port being in communication with an oil pan.
 4. A compressor as defined in claim 3, wherein said main suction port is open in said pump at a location where the pump is in the initial stage of its suction stroke and said auxiliary suction port at a location where said pump is in the latter stage of its suction stroke. 